3、Hibernate实现简单的CRUD操作

CRUD ：

Create 增加   Retrieve 读取(重新获得数据)  Update 更新   Delete  删除

PersonDao的实现如下:

package com.baowei.dao;

import java.util.List;

import org.hibernate.Session;

import com.baowei.entity.Person;
import com.baowei.utils.HibernateUtil;

public class PersonDao {

    public void save(Person person) {
        Session session = null;
        try {
            session = HibernateUtil.openSession();
            session.getTransaction().begin();
            session.save(person);
            session.getTransaction().commit();
        } catch (Exception e) {
            if (session != null)
                session.getTransaction().rollback();
            throw new RuntimeException(e);
        } finally {
            if (session != null) {
                HibernateUtil.close(session);
            }
        }

    }

    public void update(Person person) {
        Session session = null;
        try {
            session = HibernateUtil.openSession();
            session.getTransaction().begin();
            session.update(person);
            session.getTransaction().commit();
        } catch (Exception e) {
            if (session != null)
                session.getTransaction().rollback();
            throw new RuntimeException(e);
        } finally {
            if (session != null) {
                HibernateUtil.close(session);
            }
        }

    }

    public void delete(Person person) {
        Session session = null;
        try {
            session = HibernateUtil.openSession();
            session.getTransaction().begin();
            session.delete(person);
            session.getTransaction().commit();
        } catch (Exception e) {
            if (session != null)
                session.getTransaction().rollback();
            throw new RuntimeException(e);
        } finally {
            if (session != null) {
                HibernateUtil.close(session);
            }
        }

    }

    public Person findById(int id) {
        Session session = null;
        Person person = null;
        try {
            session = HibernateUtil.openSession();
            session.getTransaction().begin();
            person = (Person) session.get(Person.class, id);
            session.getTransaction().commit();
            return person;
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            if (session != null)
                session.getTransaction().rollback();
            if (session != null) {
                HibernateUtil.close(session);
            }
        }
    }

    public List findAll() {
        Session session = null;
        List persons = null;
        try {
            session = HibernateUtil.openSession();
            session.getTransaction().begin();
            persons = session.createQuery("from Person").list();
            // persons = session.createSQLQuery("select * from person").list();
            session.getTransaction().commit();
            return persons;
        } catch (Exception e) {
            if (session != null)
                session.getTransaction().rollback();
            throw new RuntimeException(e);
        } finally {
            if (session != null) {
                HibernateUtil.close(session);
            }
        }
    }

    public List page(int firstResult, int maxResults) {
        Session session = null;
        List persons = null;
        try {
            session = HibernateUtil.openSession();
            session.getTransaction().begin();
            persons = session.createQuery("from Person")
                    .setFirstResult(firstResult).setMaxResults(maxResults)
                    .list();
            // persons = session.createSQLQuery("select * from person").list();
            session.getTransaction().commit();
            return persons;
        } catch (Exception e) {
            if (session != null)
                session.getTransaction().rollback();
            throw new RuntimeException(e);
        } finally {
            if (session != null) {
                HibernateUtil.close(session);
            }
        }
    }

}